CVE-2024-31144: Xapi: Metadata injection attack against backup/restore functionality

Vulnerability summary

CVE-2024-31144 is a low (CVSS 3.8) vulnerability in xen xapi. EPSS estimates a 0.21% chance of exploitation in the next 30 days, higher than 11.9% of scored vulnerabilities.

Timeline

1. 14-02-2025
   PublishedVulnerability first disclosed.
2. 26-04-2025
   Last modifiedVulnerability information updated.

Description

For a brief summary of Xapi terminology, see: https://xapi-project.github.io/xen-api/overview.html#object-model-overview Xapi contains functionality to backup and restore metadata about Virtual Machines and Storage Repositories (SRs). The metadata itself is stored in a Virtual Disk Image (VDI) inside an SR. This is used for two purposes; a general backup of metadata (e.g. to recover from a host failure if the filer is still good), and Portable SRs (e.g. using an external hard drive to move VMs to another host). Metadata is only restored as an explicit administrator action, but occurs in cases where the host has no information about the SR, and must locate the metadata VDI in order to retrieve the metadata. The metadata VDI is located by searching (in UUID alphanumeric order) each VDI, mounting it, and seeing if there is a suitable metadata file present. The first matching VDI is deemed to be the metadata VDI, and is restored from. In the general case, the content of VDIs are controlled by the VM owner, and should not be trusted by the host administrator. A malicious guest can manipulate its disk to appear to be a metadata backup. A guest cannot choose the UUIDs of its VDIs, but a guest with one disk has a 50% chance of sorting ahead of the legitimate metadata backup. A guest with two disks has a 75% chance, etc.

• CWE-829Inclusion of Functionality from Untrusted Control SphereThe product imports, requires, or includes executable functionality (such as a library) from a source that is outside of the intended control sphere.